Android:更新 SharedPreferences

Question

我正在尝试记录我的应用程序的启动时间。为此，我需要将信息存储在设备中，即使应用程序已被终止。

我阅读了这个链接:

http://developer.android.com/guide/topics/data/data-storage.html#pref

我认为实现这一点的最简单方法是使用 SharedPreferences。所以我写了这段代码:

final String PREFS_NAME = "MyPrefsFile";


SharedPreferences settings = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
int TimesLaunched = settings.getInt("TimesLaunched", 0);

TimesLaunched++;

SharedPreferences.Editor editor = settings.edit();
editor.putInt("TimesLaunched", TimesLaunched);


editor.commit();

我第一次发现它有效，所以它从 0 变到 1，仅此而已。以下几次我启动该应用程序时没有任何反应。

谁知道哪里出了问题？

Answer 1

我在这里发布了一个我写的类，用于在他登录我的应用程序时保存用户凭据，按照您想要的方式修改它

public class SessionManager {
// Shared Preferences
SharedPreferences pref;

// Editor for Shared preferences
Editor editor;

// Context
Context _context;

// Shared pref mode
int PRIVATE_MODE = 0;

// Sharedpref file name
private static final String PREF_NAME = "TGCPrefs";

// All Shared Preferences Keys
private static final String IS_LOGIN = "IsLoggedIn";

// User name (make variable public to access from outside)
public static final String KEY_USERNAME = "email";

// Email address (make variable public to access from outside)
public static final String KEY_Password = "password";

// Constructor
public SessionManager(Context context) {
    this._context = context;
    pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    editor = pref.edit();
}

/**
 * Create login session
 * */
public void createLoginSession(String email, String password , boolean facebookCall) {
    // Storing login value as TRUE
    editor.putBoolean(IS_LOGIN, true);

    // Storing name in pref
    editor.putString(KEY_USERNAME, email);

    // Storing email in pref
    editor.putString(KEY_Password, password);

    editor.putBoolean("FB", facebookCall);
    // commit changes
    editor.commit();
}

/**
 * Check login method wil check user login status If false it will redirect
 * user to login page Else won't do anything
 * */
public boolean checkLogin() {
    // Check login status
    if (!this.isLoggedIn()) {
    /*  // user is not logged in redirect him to Login Activity
        Intent i = new Intent(_context, LoginActivity.class);
        // Closing all the Activities
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        // Add new Flag to start new Activity
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        // Staring Login Activity
        _context.startActivity(i);*/
        return false;
    } else if (this.isLoggedIn()) {
        return true;
    }
    return false;
}


public boolean isFacebookLoggedId(){
    return pref.getBoolean("FB", false);
}

/**
 * Get stored session data
 * */
public HashMap<String, String> getUserDetails() {
    HashMap<String, String> user = new HashMap<String, String>();
    // user name
    user.put(KEY_USERNAME, pref.getString(KEY_USERNAME, null));

    // user email id
    user.put(KEY_Password, pref.getString(KEY_Password, null));



    // return user
    return user;
}

/**
 * Clear session details
 * */
public void logoutUser() {
    // Clearing all data from Shared Preferences
    editor.clear();
    editor.commit();

    // After logout redirect user to Loing Activity
    /*Intent i = new Intent(_context, LoginActivity.class);
    // Closing all the Activities
    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    // Add new Flag to start new Activity
    i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

    // Staring Login Activity
    _context.startActivity(i);*/
}

/**
 * Quick check for login
 * **/
// Get Login State
public boolean isLoggedIn() {
    return pref.getBoolean(IS_LOGIN, false);
}
}

您需要做的就是修改它并调用 get prefs last counter 并在您的初始屏幕上将其递增 1(如果这是您的工作方式或您想要使用的任何策略)